This invention relates to construction of cementitious structures. In particular, the invention relates to a system and method for using inserts and a coating for architecturally finishing seams between roof panels of cementitious materials.
Cementitious roof panels, specifically Autoclaved Aerated Concrete (“AAC”) roof panels, have been used for many years. There are many advantages of cementitious roof panels: durability, no rot nor decay, and strength. AAC roof panels additionally have insulation value due to their mass and the fact that they are aerated.
Applying a thin coating over AAC roof panels to weatherproof the roof has disadvantages. A primary disadvantage is that it is aesthetically undesirable because panel seam joints are difficult to repair. Moreover, even if the panel seam joints are repaired, the resulting large, smooth monotonous roof surface is unbecoming.
In the background art, these problems of using AAC roof panels have been solved by using expensive secondary roofing materials to weatherproof the roof. Normally, a pressure treated furring strip board is attached to AAC roof panels and then plywood sheets are nailed to the furring strips. A weatherproof asphalt paper is then stapled over the wood decking. Finally, a finished roofing system, such as asphalt shingles, etc. is installed. This approach to weatherproofing ACC roofs is accomplished at greater expense and labor than is necessary to weatherproof conventional wood roofs. Additionally, the asphalt shingles and other materials need to be replaced after about fifteen years so there is great amount of pollution in landfills, etc. There is a strong need for an environmentally friendly, permanent roof system.
It is usually cost prohibitive to add more expensive types of roofing, e.g., standing seam steel roofing, to an AAC roof. Moreover, standing seam steel roofs have an enormous amount of embodied energy and use valuable steel that would be better used for other purposes.
The finishing of the interior surface of AAC roof panels requires that sheetrock or thick plaster be applied in order to produce an architecturally acceptable interior finish. The panels are normally installed horizontally, spanning from one interior load-bearing wall to another. The (first) lowest panel is placed initially and secured and then the subsequent panels are installed by resting them on the first panel. The panels are normally not installed vertically (from fascia to ridge line) due to the butt ends not having a place to rest, and the difficulty of aligning the butt ends to produce a uniform (flush) exposed edge. Therefore the background art's added labor and materials required to construct a habitat employing AAC roof panels were excessive to extent the inherit advantages of ACC could not be appreciated.
For the reasons presented above, background art cementitious roof panel systems have been covered with conventional roofing materials at great additional labor, waste of materials and cost. The applicant's disclosures of roof coating, gravity fed gutters and panel fascia have provided an environmentally-friendly and cost-effective weather proofing system. There is a very strong need for environmentally-friendly roofing materials for AAC structures that exhibit a low quantity of embodied energy that are aesthetically attractive so consumers will be motivated to purchase them.
There is a very strong need for manufacturing and construction processes wherein all the inherent advantages of AAC roof panels can be economically actualized. The optimum solution is for a simplified and economical field installation of a superior product that also would be architecturally appealing.
The background art is characterized by U.S. Pat. Nos. 7,104,020; and 7,204,060 and by U.S. Patent Application Nos. 2001/0045070; 2002/0078659; 2002/0174606; 2006/0003144; and 2007/0056223; the disclosures of which patents and published patent applications are incorporated by reference as if fully set forth herein. In the background art, AAC roof panels are installed horizontally to avoid the problems inherent in installing cementitious roof panels vertically. Background art structures that incorporated vertical roof panels are simple single ridge roofs. There are no examples of economically-viable, vertically-installed, cementitious roof panels on a roof with multiple hips and valleys. Background art AAC roof systems lack the architectural, aesthetic advantages of other roofing systems. Also the smooth roofs have problems of mortar in seams creating additional work to eliminate noticeable surface irregularities. Standing seam steel roofs have an enormous amount of embodied energy and use valuable steel that would be better used for other purposes.